water problem

placethefive wrote:
We purchased a new class c mh Forest River Sunseeker, 25 ft. 2017. at the time of purchase, I received a 25 ft. water hose. We used this hose 6 or 7 times with no problems. After several times, I realized that I was close to water. So, I purchased a 10 foot hose. My problem is, every time I connect the short hose to the city water port, it fills my fresh water tank over night. Seems crazy but it does happen and the service folks can not fix it. Anyone ever heard of this?????

It is not that the service folks can not fix it, it is that they do not want to. They have to fix under the warranty agreement.

Only 2 things it could be.

1: Anderson Valve
2: Water pump

Long hose...short hose-----doesn't matter. That has NOTHING to do with overfilling your fresh water tank

Only 2 ways water goes into fresh water tank
Via the 'normal' fill (either gravity fill port OR 'FILL' valve)
OR back-flowing thru pump via internal check valve


SO if you have a gravity fill port...........then pumps internal check valve is allowing back-flow

IF you have a 'Fill' valve ---it could be leaking thru, not closing OR pumps internal check valve

If you have a 'Fill' valve you can disconnect suction line at pump and then using city water see if water back-flows out of pump.
No back-flow then FILL valve is problem
Back-flow then pump check valve is problem


With fresh water tank full....secure city water and turn on pump. Use up the tank allowing flow thru pump to flush any stuff off pump check valve



IF 'Service Folks' can fix it---then it's because they do NOT want to or they are NOT someone I would want doing ANY repairs
Overfilling fresh water tank is a very common issue.....pump check valves and/or fill valves being problems is common
This can't be the first time these 'Service Folks' have had to deal with it

I discovered I had the same problem but not hose length related. My problem was the check valve in the water pump head was leaking. For a temporary fix I installed a check valve on the output side of the pump. Problem solve. I will bet it will backfill the tank with the longer hose but as you said it doesn't, it is a mystery to me.

To me, it seems the dealer should be responsible for the problem until he can prove it is a faulty pump and the pump manufacturer is responsible but the dealers job to get reimbursed not yours.

Just a guess, maybe with the short hose the pressure is hitting the check valve full force. With the longer hose pressure is a bit more gradual. To test this theory with the short hose, I would just crack the water valve just so the water starts to flow, wait 30 seconds to a minute then gradually open the valve all the way.

If you fill your fresh water tank with only a gravity fed hose, then the only way to back fill your tank is in reverse through the water pump. Normally there is a built in check valve in the pump.

However, if you fill your fresh water by swinging a valve while connected at both the shore water tap, and the side of your rig with a hose, then one would suspect a very small amount of water bypass in the tap or valve instead of the pump.

Try getting a water pressure regulator. Sites where you use the short hose may have higher pressure and causing water to bypass the pump check valve, if so you may need to rebuild the pump or replace.

Is the water pressure perhaps higher where you use the shorter hose?

Is there a gravity fill port underneath the city water connection that might collect drips from a hose that's not sealing well?

Strange, but I can not make it happen with the long hose.

Weird and unexplainable!!!